Rex Ryan made official yesterday what was assumed he had planned all along: LaDainian Tomlinson will start at running back for the Jets on Sunday against the Chargers, his team for nine Hall of Fame seasons.

The captivating question once that first offensive snap has taken place is whether Tomlinson — by virtue of his sheer will and it factor — will allow Ryan to take him out of the game.

Because if you think Tomlinson is taking Ryan starting him against his former team as a mere ceremonial gesture, you don’t know Tomlinson very well.

Someone who knows Tomlinson as well as anyone, former Chargers and Jets fullback Lorenzo Neal, told The Post that Tomlinson’s “will and desire will turn the clock back five years in this game.”

“LT has been looking forward to this game,” said Neal, who said he speaks to his former teammate every week or so. “You know San Diego is going to want to save face and try to key on stopping LT, but they don’t have the will that he has. There is no way LaDainian Tomlinson won’t have a big game Sunday.”

Asked what will be coursing through Tomlinson’s veins at game time, Neal said simply: “Controlled rage.”

The Jets plan for their running game remains to feature Shonn Greene, who they still believe will be what Ryan calls the “bell cow.”

But there was a clear shift in the rotation in Monday night’s game, with Tomlinson playing more on first and second down than he had been this year.

As for Sunday, it might be difficult to wrest Tomlinson from the field without a pack of body guards.

“He might be a guy to get the ball to because he might be a guy playing with a little chip on his shoulder,” tight end Dustin Keller said. “He’ll be amped and ready.”

Tomlinson, as classy and low-key a pro athlete as there is, said all the right things yesterday about playing his former team — the one that unceremoniously rid itself of him two years ago after he’d logged 12,490 rushing yards, caught 530 passes and scored 153 TDs while turning the moribund franchise into a perennial contender.

“I don’t look at it like trying to get even,” Tomlinson said. “I’m not someone who holds grudges or tries to prove anybody wrong. I had a great nine years there, but I’m not going to make it bigger than what it is.”

There are others close to Tomlinson, though, who expect to see that controlled rage Neal talked about.

“He probably wouldn’t say it, but I think this is a payback game for him,” running back Joe McKnight said. “I think he’s got a little revenge in him. He wants to take some vengeance out on the old Chargers. I’m thinking he’s going to have a big game.”

Neal made it clear how “disappointed” and “hurt” Tomlinson was about the way it ended in San Diego.

“In my personal opinion, I don’t think LT should have ever worn another jersey other than the San Diego Chargers,” Neal said. “You just don’t treat greatness that way. That’s not the way you treat a first-ballot Hall of Famer. It’s not how you treat the guy that single-handedly put San Diego on the map, took them out of the dark ages.

“When you’re willing to ride with this person, you should be willing to die with that person.”

The Jets locker room is filled with guys who revere Tomlinson as the ultimate leader and are willing to do just that with him.

“Everything he does is powerful,” defensive tackle Sione Pouha said. “Because he’s so low key and such a quiet guy, when he does speak it’s like scripture. You pay attention because he doesn’t speak nonsense. You know it’s coming straight from his heart.”

Receiver Santonio Holmes said he was “super excited” when he heard Tomlinson would start the game.